Advances in the field of solid state electronics have made possible the development of various devices for electronically recording and/or manipulating images. These devices use a solid state image sensor, such as a charge coupled device (CCD), to sense the image forming light and a separate recording medium to record and store the picture. One example of such a device is an electronic still camera The solid state image sensor is built into the camera and is located at the focal point of the camera lens, i.e., at the same location that film is located in a photographic camera. When the camera shutter is activated, light is focused by the lens onto the image sensor. Light is detected by discrete cells within the image sensor and the light energy is converted into an electrical charge within the cell. The amount of charge is a measure of the light energy absorbed by the cell. When an appropriate voltage is applied to the cell, the charge can be transferred out of the cell to where the charge can be recorded and stored.
In some image recording devices it is possible to store images with various resolution settings. The amount of information or data contained in the image produced by the solid state imaging device increases as the desired resolution increases. As a result, images taken at high resolution settings need more space in a storage device than pictures taken with a low resolution setting because of the extra image data. For example, high resolution images can take up to four times the amount of storage space needed for low resolution pictures.
In some prior art still electronic cameras, a manual resolution button is provided for manually changing the resolution of the camera from high to low or from low to high. Since the high and low resolution pictures are stored in the same memory means, there may occur a situation when there is not enough available memory in the memory means to store a high resolution picture but there is enough available memory in the memory means to store at least one low resolution picture. Of course, a user can manually change the resolution setting when this occurs. However, a user may forget that there is available space in the memory means for low resolution pictures after the camera indicates that a high resolution picture cannot be taken. In addition, it may not be convenient or even possible to switch from a high resolution setting to a low resolution setting during a fast sequence of taking pictures.